Neuroprotection of geniposide against hydrogen peroxide induced PC12 cells injury： involvement of PI3 kinase signal pathway

Aim： Oxidative stress plays a critical role in the pathogenic cascade leading to neuronal degeneration in AD. Consequently, the induction of endogenous antioxidative proteins by antioxidants seems to be a very reasonable strategy for delaying the disease＇s progression. In previous work, we identified the neurotrophic and neuroprotective effects of geniposide, which result from the activation of glucagon-like peptide I receptor （GLP-1R）. In this study, we explore the role of PI3 kinase signaling pathway in the neuroprotection of geniposide in PC12 cells. Methods： Cell viability was determined by MTT assay. Apoptosis was detected by Hoechst and PI double staining. The protein expression of Bcl-2 and phosphorylation of Akt308, Akt473, GSK-313, and PDK1 was measured by Western blot. Results： Geniposide induced the expression of the antiapoptotic protein Bcl-2, which inhibited apoptosis in PC12 cells induced by H202, and this effect could be inhibited by preincubation with LY294002, a selective inhibitor of PI3K. Further-more, geniposide enhanced the phosphorylation of Akt308, Akt473, GSK-313 and PDK1 under conditions of oxidative stress. Conclusion： These results demonstrate that the PI3K signaling pathway is involved in the neuroprotection of geniposide in PC12 cells against the oxidative damage induced by H202 in PC12 cells.